Natural justice, on the other hand, includes the principles of natural law that have their origin in nature. Such principles do not arise in people`s minds “by people who think this or that.” The principles of natural law apply everywhere with equal force, just as fire burns in Greece and Persia. Aristotle ensured natural justice by adopting the commandments of natural law as the norm of legal validity. Positive laws that violate natural laws are repealed. (Aristotle, Nicomachean Ethics, 1134b). Protagoras accepted the duty to obey the law. Since no moral or legal code is truer than another, no individual should assert his moral or legal judgments over those held by the state. Society is called to preserve humanity. The survival of society, in turn, requires respect for law and custom. Men must obey the laws and customs of the state as long as they function healthily. (Plato, Protagoras, 322d; Theaetetus, 167b).

The second way Aristotle ensures natural justice is by promoting virtue. Aristotle believed that human happiness depended more on virtue than on freedom. The government is therefore responsible for creating a virtuous state, and this is best achieved by law. Although virtue involves more than mere conformity to the law, virtue will only develop and flourish in a state that supports the legal application of virtue. The state, through its laws, must provide moral education to make its citizens just and good. Otherwise, the political system of the state will be undermined and its citizens harmed. (Aristotle, Nicomachean Ethics, 1179b; Policy, 1280b, 1310a, 1337a). In the 1980s, Dworkin radicalized his views on these issues by attempting to base his antipositivist legal theory on a general theory of interpretation and emphasizing the profound interpretive character of the law. Despite the fact that Dworkin`s interpretive legal theory is extremely sophisticated and complex, the essence of his reasoning from interpretation can be summarized in a fairly simple way. The main argument consists of two main premises. The first thesis is that determining what the law requires in each individual case necessarily requires interpretative considerations.

Any statement of the form “According to the law in (S)(x) has a right/duty, etc., of (y)” is a conclusion of one interpretation or another. Now, according to the second premise, interpretation always involves evaluative considerations. More specifically, interpretation may not be a mere finding of fact or a matter of evaluative judgment per se, but an inseparable mixture of both. It is clear that someone who accepts these two theses must conclude that the separation thesis is fundamentally flawed. If Dworkin is correct in both theses, it certainly follows that determining what the law requires always involves evaluative considerations. One could try to answer this argument in two ways. A natural, though ultimately unsuccessful, answer is that interpreting something as the best example of its kind it can be does not require taking that kind to be good. Saying that Bernie Madoff was (for a while) the best con man in history doesn`t mean you approve of the fraud. Therefore, to say that the law must be such and such in order to be a good example of this kind does not require thick judgments.

Nevertheless, there is a deeper or more interesting sense in which Dworkin`s view makes legal theory inherently evaluative. For Dworkin, legal theory is an interpretive enterprise, and offering a constructive interpretation of legal practice requires interpreting it in its best moral light. In order to be able to offer an interpretation of legal practice, it would therefore be necessary to take a position on which of the available modes of interpretation is morally better than the others. Of course, this does not necessarily require claiming that the law is good in terms of particular interpretation – period. But it seems at least necessary to say that some constructs of legal practice are morally better than others. This seems to be a thick, albeit comparative, judgment claim. Moreover, one cannot make such comparative judgments without having an opinion as to what would make one interpretation of legal practice morally better than another. At least in this sense, legal theory would be seen as an interpretive enterprise in Dworkin`s sense, legal theory as inherently evaluative in the sense we are dealing with here. However, the most interesting and, from a positivist point of view, the most problematic aspect of legal principles is their moral dimension. According to Dworkin`s theory, principles, unlike legal rules, which may or may not have something to do with morality, are essentially moral in their content. In fact, it is partly a moral consideration that determines whether a legal principle exists or not. What for? According to Dworkin, there is a principle of law if that principle results from the best moral and political interpretation of past judicial and legislative decisions in the area concerned.

In other words, legal principles occupy an intermediate space between legal norms and moral principles. Legal regulations are drawn up by recognized institutions and their validity results from their source. Moral principles are what they are by virtue of their content, and their validity depends purely on the content. Legal principles, on the other hand, derive their validity from a combination of source and substantive considerations. As Dworkin put it in the most general terms, “According to the law as integrity, legal propositions are true if they are contained in or flow from the principles of justice, fairness and due process that offer or derive from the best constructive interpretation of the legal practice of the community” (Dworkin 1986, 225).